Acute restraint stress induces hyperalgesia via non-adrenergic mechanisms in rats

Abstract

Analgesia or hyperalgesia has been reported to occur in animals under different stress conditions. This study examined the effect of acute restraint stress on nociception in rats. Acute restraint stress produced a time-dependant decrease in pain threshold; this hyperalgesia was not affected by prior administration of adrenergic blockers suggesting the non-involvement of adrenergic mechanisms. The hyperalgesia may however result from a change in the affective state of the animal and not from a change in sensory processing of noxious stimulus.

Keywords: stress, hyperalgesia, tail-flick test, sympathetic nervous system

African Journal of Biomedical Research Vol. 8(2) 2005: 123-125